Methods and Apparatuses for Water Purification

ABSTRACT

An apparatus for generating purified liquid from an input liquid, comprises, an evaporation chamber flooded with the input liquid and wherein the evaporation chamber generates saturated gases and comprises a shared wall with the condensation chamber and wherein the evaporation chamber is configured to generate evaporation cavities and condensation cavities on respective sides of the shared wall for a 2-phase counter flow of a liquid phase component and a gaseous phase component in composite flows for a 2-phase to 2-phase direct latent heat exchange. A condensation chamber has channels disposed in the input liquid, wherein liquid-saturated gases are generated therefrom in the evaporation chamber. The apparatus is operated as a four-port counter-flow heat exchanger where two different fluids are exchanging heat based on the inlet ports of both fluids being on opposite sides and the outlet ports of both fluids are also on opposite sides of the evaporator and condenser.

CROSS REFERENCE

This application claims priority from a provisional patent applicationentitled “Method and Apparatus for Water Purification” filed on Jan. 11,2012, having an Application No. 61/585,293, and from a provisionalpatent application entitled “Methods and Apparatuses for WaterPurification” filed on Nov. 16, 2012, having an Application No.61/727,661. Said applications are incorporated herein by reference. Thisapplication is also Continuation in Part (CIP) of and claims priority toearlier filed U.S. Non-Provisional patent application Ser. No.13/733,842 filed Jan. 3, 2013 in allowance for issue and is incorporatedherein by reference in its entirety, including all amendments thereof.

FIELD OF INVENTION

This invention generally relates to methods and apparatuses for waterpurification, and, in particular, to methods and apparatuses for waterpurification using humidification-dehumidification (“HDH”).

BACKGROUND

Lack of clean drinking water is still the primary cause for disease,suffering and ultimately death in many parts of the world. Even wherewater is available to the public, often times the available water iscontaminated by chemicals used in agriculture, e.g., by industrialcontamination or by sewage seeping into the water supply. Additionally,areas in close proximity to an ocean have a water source of highsalinity, and consequently not suitable for drinking.

Water that is centrally treated is also not safe in many parts of theworld as positive pressure is not maintained at all times in thedistribution network for the water. Leaks in the distribution networkcan cause contamination of the water in this system. Furthermore, themultiple points where the water is stored after an initial treatment,e.g., storage tanks, lack any kind of continuous supervision andsanitation. In particular, storage tanks are not cleaned regularly,thereby becoming sources of contamination and having an ecosystem oftheir own with all sorts of insects, animals, bacterial growth, andalgal growth.

The use of bottled water has grown in metropolitan cities. However, inrural areas, this is not possible, nor desired, since transportation ofthe bottled water to the end users is often difficult and since theindiscriminate use of plastics for the bottled water has caused adisposal and recycling nightmare.

In effort to solve such dilemmas with existing water supplies, therehave been extensive efforts in the field of filtration to purify watersources. Existing technologies for filtration require the use ofcontinuously replaceable consumables having multiple stages of filtersto maintain the system in optimal state. Once these consumables are notreplaced due to neglect or non-availability, the quality of the outputwater (otherwise referred to as product water) from these systems isseverely degraded and in many cases becomes worse than the actual inputwater due to internal contamination.

There are two general classes of water purification technologies: one isbased on the principle of evaporation and condensation, or thermaldistillation, and the other is based on membrane filtration. Amongmembrane filtration techniques, reverse osmosis (“RO”) andelectro-dialysis are the most representative. For thermal distillation,there are various vacuum thermal desalination techniques available forlarge, high capacity plants, as well as atmospheric distillationtechniques, also called HDH, which are more suited for smallpurification devices.

The rapid advances of the RO based technologies in recent years havemade RO the favorite among all water purification technologies owing toits low initial capital costs and high energy efficiencies. For seawaterdesalination, the specific energy cost of RO (when energy recovery isused) is between 4 to 7 kWh/ton of purified water, while most largethermal desalination plants which use MSF (multiple stage flashevaporation) and MED (multiple effects evaporation distillation) havespecific energy expenditure between 20 to 200 kWh/ton. The HDH systemsfare even worse in this respect with a specific energy cost ranging from150 kWh/ton to more than 400 kWh/ton. The sole exception to thiscomparison is mechanical vapor compression (“MVC”) which can achieve aspecific energy consumption level comparable to that of RO, with a rangefrom 4 kWh/ton to just below 12 kWh/ton).

However, thermal distillation generally produces highly purified waterwith a TDS (total dissolved solid) level well below 1 ppm (part permillion), while it would be impractical for RO plants to produce waterpurity of less than 20 ppm or so. RO is also unable to filter out lightweight dissolved chemical molecules if their sizes are comparable to theaverage pore size of the RO membrane. RO is also far more prone tofouling, scaling, and plugging of the membrane, and rapid oxidation caneasily destroy the membrane if it is directly exposed to air. While allwater purification techniques require pretreatments or pre-filtering toreduce the probability of fouling and to ensure proper operation of themain purification process, RO typically requires more pretreatments toprotect its membranes from failures, and the standard half-life of an ROmembrane is about two years, hence the costs of its consumablesrepresent a large part of its total operational cost.

The low initial cost advantage of RO lies primarily in its exceptionalpacking density, or area to volume ratio. While thermal distillationrelies on heat exchange surfaces to reclaim latent heat in order tolower its energy cost, RO and other membrane techniques rely on largefiltration surface to separate clean water from brine, hence packingdensity plays a very important role in both classes of purificationtechnologies. Having a large surface area not only can increase waterproduction, but also can reduce the surface loading factor, which is therate of purified water production per unit surface area. Reducingsurface loading can drastically improve operational efficiency at thecost of reducing water production rate since it greatly reduces internalentropy productions in both RO systems and thermal distillation plants.

Although MVC thermal distillation technology has largely caught up to ROin terms of specific energy cost, its initial capital cost is still farhigher than comparable RO technologies owing to its much lower packingdensity. HDH systems are typically lower in costs than RO and have thepotential of producing purer water than RO because of its lowtemperature atmospheric pressure operations. However, the extremely lowspecific energy efficiencies of these systems have been the mainobstacles to their wide acceptance.

Another drawback is that existing distillation technologies are far toocostly to implement since these technologies use a large amount ofenergy to convert water to steam before recondensing the saturated gasesand since these technologies are typically built with expensivestainless steel or other costly metals.

One of the major disadvantages of the existing distillation techniquesis the requirement to employ high strength materials for the containmentand heat exchange walls. HDH partially solves the problem by usingatmospheric pressure evaporation (humidification) and condensation(dehumidification) which obviates the need to utilize high strengthmaterials and replace them with cheaper and thinner materials such asplastic substrates.

Another disadvantage of the existing distillation techniques is thecomparatively low packing density, or surface to volume ratio of theheat exchange surfaces. By way of example, spiral wound filters andhollow tube RO filters have packing densities which are orders ofmagnitude higher and permit smaller filtration plants to be built forthe same capacity. Higher packing density in the case of distillationplants could also mean lower loading on the heat exchange surfaces forthe same water production capacity, which drastically improves latentheat recovery efficiency while maintaining the same water productioncapacity.

Still another disadvantage for some of the existing distillationtechniques is the lack of a direct heat exchange in both the evaporatorand the condenser. Typically both the evaporator and the condenser havecross flows to exchange heat in a conventional manner but this does notbring about any novel and efficient advantages.

FIG. 1 illustrates a diagram of a prior art method and apparatus forwater purification using HDH. The prior art comprises a vertical heatexchange wall 10 between the evaporation chamber 12 and the condensationchamber 14. Feed water 16 is sprayed downward, near the top of theevaporation chamber 12, via a sprayer 18. An air blower 20 blows againsta falling mist 28 of the feed water from the bottom of the evaporationchamber 12. There is also a brine tray 22 at the bottom of theevaporation chamber 12 for storing concentrated brine 24, the remnantsof the feed water that did not evaporate. The brine 24 in the brine tray22 can be removed via a brine outlet 26 of the evaporation chamber 12.The vertical heat exchange wall 10 allows latent heat from thecondensation chamber 14 to flow to the evaporation chamber 12 (seedotted arrows for that general direction). As a portion of the feedwater 16 evaporates, the saturated gases are directed to thecondensation chamber 14. The condensation chamber 14 then condenses thesaturated gases and produces product water 30. The product water 30 ispooled and directed out of the condensation chamber via an outlet 34 forstorage or use. The non-condensed gases are directed out of thecondensation chamber 14 via an air outlet 32 near the bottom of thecondensation chamber 14 in an open loop process. Since the latent heatexchange process does not fully recover the latent heat for reuse, anadditional heat source in the form of a heater 36 is required tointroduce further steam into the condensation chamber 14 and to preheatthe feed water.

By placing the condensation chamber 12 side by side with the evaporationchamber 14, separated only by a common wall 10 which serves as the heatexchange wall, the latent heat generated from the condensation of thewater vapor is transferred to the evaporator to heat the feed water,which eliminates one of the major drawbacks of the HDH distillationprocess.

Unfortunately, due to the design of the prior art, severalinefficiencies are apparent. First, the vertical heat exchange wall 10is not fully utilized since most of the latent heat transfer isinefficiently transferred from gases in the condensation chamber 14 toother gases in the evaporation chamber 12. This is due to the verticalarrangement of the heat exchange wall 10 and due to the misting of feedwater 16 downwards into the evaporation chamber 12.

In a vertical heat exchange wall arrangement, filmwise condensation,first studied by Nusselt, is generally recognized as being a moreefficient condensation mechanism as the latent heat released at theouter boundary of the liquid film condensate is transferred directly tothe heat exchange surface without going through gases. However, in orderfor this to occur, the heat exchange surface must have a strong affinityto said liquid, i.e., the surface must be strongly hydrophilic. This isnot the case with the prior art with its plastic heat exchange surface.The low affinity (wettability) of the plastic heat exchange surface toliquid makes it hard for the condensing liquid on the condenser side toform filmwise or dropwise condensation, and to form filmwise evaporationon the evaporator side; this drastically reduces the heat transferefficiency and lowers the fraction of the latent heat that can berecovered.

Lower latent heat exchange performance increases internal entropyproduction. As will be clear below, any increase in internal entropyproduction decreases total system efficiency and/or reduces waterproduction rate. Since mechanical work does not introduce additionalentropy flow into the system, it is preferred over direct heat input ingeneral cases. However, when the input heat is derived from waste heator other low cost heat sources, it might be more preferable to use thoseheat sources as the input instead of mechanical work input despite thelatter's more efficient utilization of the energy.

In addition, the open loop process does not reuse the sensible heat thatstill remains within the non-condensed gasses that are routed via theair outlet 32 from being reused. Although rerouting the non-condensedgases to the bottom of the evaporation chamber can recoup some of thewaste heat, such a process is inherently inefficient owing to the largetemperature difference between the non-condensed gas and the feed water.The evaporation chamber 12 also requires a large volume to generate anyappreciable amount of product water owing to the relatively low surfaceto volume ratio of the prior art design.

Another main drawback of said prior art is its use of hot steaminjection to provide the needed heat input for evaporation. As will beexplained in a great deal more detail below, any direct heat inputthrough hot fluid injection or direct heating of the system introduces acontinuous stream of entropy into the system which must be ejected inorder to keep the total entropy within the system finite. Such entropyejection leads to increased energy consumption which decreases theoverall system efficiency and/or production rate.

Therefore, it is desirable to present novel methods, systems andapparatuses for filtration that addresses all of the above drawbacks.

SUMMARY OF INVENTION

An object of this invention is to provide an apparatus and system usingHDH that permits efficient direct latent heat transfer in a costeffective manner via a bulk/percolating immersion evaporation andclosed-loop air recirculation system using atmospheric pressuredistillation. The disclosed apparatus generates purified liquid from aninput liquid and includes an evaporation chamber flooded with the inputliquid and wherein the evaporation chamber generates saturated gases andcomprises a shared wall with the condensation chamber and wherein theevaporation chamber is configured to generate evaporation cavities andcondensation cavities on respective sides of the shared wall for a2-phase counter flow of a liquid phase component and a gaseous phasecomponent in composite flows for a 2-phase to 2-phase direct latent heatexchange. A condensation chamber has channels disposed in the inputliquid, wherein liquid-saturated gases are generated therefrom in theevaporation chamber. The apparatus is operated as a four-portcounter-flow heat exchanger where two different fluids are exchangingheat based on the inlet ports of both fluids being on opposite sides andthe outlet ports of both fluids are also on opposite sides of theevaporator and condenser.

Another object of this invention is to provide a filtration apparatuswherein a plurality of evaporation chambers and condensation chambersare placed to provide a large overall latent heat exchange surface toensure low loading factor for said exchange surface for enhanced latentheat recapturing performance even at high water production rates.

Yet another object of this invention is to provide a filtrationapparatus which utilizes dropwise condensation and a percolating floodedevaporation chamber to enhance latent heat exchange performance.

A further object of this invention is to provide a filtration systemwhere capillary force is employed within an aerodynamically efficientscreen to prevent entrained liquid droplets from entering the compressorchamber and to reduce the pressure drop of the mist retaining screen dueto the drag force exerted on the gas flow by the screen.

Even more so, another object of this invention is to provide a systemwith an impermeable hollow fiber heat exchange matrix which combinesevaporation and condensation chambers into a single fabric to rivalother filtration systems in packing density (active surface area tovolume ratio), e.g., the spiral wound and semi-permeable hollow fibermembranes for a reverse osmosis filtration system.

Yet still another object of this invention is to provide an apparatuswith enhanced brine sedimentation means to keep the brine concentrationin the evaporation chambers to a controlled level.

Yet still, another object of the invention is to provide a filtrationsystem with electrical gas filtration for the recirculatingincondensable carrier gases to remove contaminated suspendedparticulates and liquid droplets from the input gas stream to thecondensation chambers.

It is yet another object of the present invention to provide afiltration system with self-monitoring capabilities with distributedsensors and actuators for the purpose of predicting and estimating theinternal entropy production rate, and steering the system toward optimalperformances based on such real-time sensor inputs.

It is a further object of the present invention to provide a filtrationsystem with the ability to switch amongst a multitude of energy sourcesin order to minimize operational costs.

It is still another object of this invention to provide a filtrationsystem with polymer heat exchange substrates with improved anisotropicbulk thermal conductivity and higher mechanical strength for the purposeof enhancing the latent heat transfer characteristics of said polymersubstrates.

Other objects and advantages of the present invention shall becomeapparent to those skilled in the art by referencing to the remainingportions of the specifications together with their respective drawings.

Briefly, the present invention discloses an apparatus for generatingpurified liquid from an input liquid, comprising, an evaporationchamber, wherein the evaporation chamber is flooded with the inputliquid; and a condensation chamber having channels, wherein the channelsare disposed in the input liquid, wherein liquid-saturated gases aregenerated from the input liquid in the evaporation chamber, wherein theliquid-saturated gases are guided into a first end of the channels, andwherein the purified liquid is outputted at a second end of thechannels.

An advantage of this invention is that low cost methods and apparatusesfor water purification are provided.

Another advantage of this invention is that low energy methods andapparatuses for water purification are provided.

Yet another advantage of this invention is that energy efficient methodsand apparatuses for water purification are provided.

Still another advantage of this invention is that the produced waterquality remains high and consistent.

A further advantage of this invention is the ability of the presentsystem to self-monitor the states of the system operation andautomatically retune said system toward optimum performances.

A still further advantage of this invention is that a plurality ofenergy sources can be utilized and switched amongst them to provide nearoptimum operational conditions in real-time.

DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, aspects, and advantages of theinvention can be better understood from the following detaileddescription of the preferred embodiment of the invention when taken inconjunction with the accompanying drawings in which:

FIG. 1 illustrates a diagram of a prior art method and apparatus forwater purification using HDH.

FIG. 2a illustrates a general representation of a thermal dynamic systemwith fixed boundaries in relation to the present invention.

FIG. 2b illustrates a diagram of the present invention for waterpurification having a flooded evaporation chamber.

FIG. 3 illustrates a diagram of another embodiment of the presentinvention for water purification having an additional auxiliary steamgenerator.

FIG. 4 illustrates a diagram of the present invention for waterpurification having multiple channels for the evaporation chamber andcondensation chamber.

FIG. 5 illustrates a diagram of a water purification apparatus of thepresent invention having multiple panels for the evaporation chamber andcondensation chamber.

FIG. 6 illustrates a diagram of a distal manifold of the waterpurification apparatus of the present invention.

FIG. 7 illustrates a diagram of a proximal manifold of the waterpurification apparatus of the present invention.

FIG. 8 illustrates a perspective view of a water purification apparatusof the present invention.

FIG. 9 illustrates a top view of a panel of a condensation chamber ofthe present invention having several perforations through the evennumbered channels of the panel.

FIG. 10 illustrates a top view of a panel of a condensation chamber ofthe present invention having several perforations through the oddnumbered channels of the panel.

FIG. 11 illustrates a zoomed-in perspective view of a panel of acondensation chamber of the present invention having severalperforations through some of the channels and a spacer.

FIG. 12 illustrates a zoomed-in perspective view of several panels of acondensation chamber of the present invention.

FIG. 13 illustrates a grouping of tubes to form a condensation chamberof the present invention.

FIG. 14 illustrates a rectangular tube cartridge for the condensationchamber of the present invention.

FIG. 15 illustrates a tube of the condensation chamber of the presentinvention having a spacer.

FIG. 16a illustrates a zoomed-in view for an end of a tube of thecondensation chamber of the present invention.

FIGS. 16b-16c illustrate various cross sectional shapes for a spacer ofa tube of the present invention.

FIG. 17 illustrates a diagram of another embodiment of the presentinvention for water purification having a rectangular tube cartridge.

FIG. 18 illustrates a perspective view of a demister of the presentinvention.

FIG. 19 illustrates an additional perspective view of a demister of thepresent invention.

FIG. 20 illustrates an aerodynamic fin of a demister of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following detailed description of the embodiments, reference ismade to the accompanying drawings, which form a part hereof, and inwhich is shown by way of illustration of specific embodiments in whichthe present invention may be practiced.

The below description described the invention in relation to purifyingdirty water. However, it is understood that the present invention can beapplied for purifying a host of other liquids, including saline water,contaminated water, or other liquids.

The present invention overcomes many deficiencies of the current art byusing the minimum entropy production principle to maximize latent heatexchange efficiencies and by increasing the packing density of the heatexchange surfaces. Additionally, the present invention providesreal-time adaptive control of the system operation to continuouslyretune the system parameters as well as switching to alternate energysource to maintain low operational costs.

FIG. 2a illustrates a general representation of a thermal dynamic systemwith fixed boundaries in relation to the present invention. Heat andmass flows are transported across the boundaries of a thermal dynamicsystem. The total entropy of the system is a state variable, hence itsvalue must remain the same during steady states such as when a thermaldistillation plant has reached a steady state operation condition, orafter a complete thermal dynamic cycle, such as those that occur in aninternal combustion engine Likewise, the total internal energy of thesystem is also a state variable.

The first law of thermal dynamics (energy conservation law) states thatthe time rate of change of the total internal energy of the system mustequal the total heat input (the convention that a heat output isequivalent to a negative heat input) plus the sum of the enthalpy inputswhenever a mass flow is present, and the net power input. It reads,

$\begin{matrix}{\frac{dU}{dt} = {{\sum\limits_{j}{\overset{.}{Q}}_{j}} + {\sum\limits_{k}\overset{.}{{m_{k}h_{k}} + P}}}} & (1)\end{matrix}$

and the second law of thermal dynamics states that the time rate ofchange of the total system entropy is equal to the sum of the entropyinput rate associated with each direct heat input plus the sum of theentropy flow associated with each mass flow, plus the sum of theinternal irreversible entropy production rates. The irreversible entropyproduction rates must all be positive and could only vanish but nevernegative under idealized theoretical conditions. It reads,

$\begin{matrix}{\frac{dS}{dt} = {{\sum\limits_{j}\frac{\overset{.}{Q_{j}}}{T_{j}}} + {\sum\limits_{k}\overset{.}{m_{k}s_{k}}} + {\sum\limits_{l}{\overset{.}{S}}_{irrevl}}}} & (2)\end{matrix}$

where S and U are the total system entropy and total system internalenergy, respectively, m_(k) is the mass flow rate associated with theposition (or port) k, P is the net power input (negative if output), cthe specific enthalpy (per unit mass) associated with the position k,and s_(k) the specific entropy associated with the mass flow at positionk. S_(irrevl) is the internal entropy production rate at some internallocation l. The latter must be positive in accordance with the secondlaw of thermal dynamics. For steady states, both

$\frac{dS}{dt}\mspace{14mu} {and}\mspace{14mu} \frac{dU}{dt}$

must vanish for reason already discussed.

By ways of an example, consider an idealized thermal distillation system340 comprising an evaporation/condensation main block, a dirty waterfeed at position 1, an outlet for the distilled water and another onefor the rejected brine at position 2. The distillate and brine areassumed to have the same thermal dynamic parameters for simplicity,although that can be easily generalized to having distinct outlets. Theassumption is valid when the ejected brine and the distillate areclosely coupled thermal dynamically, and the brine's TDS concentrationis not significant enough to affect the specific entropy and enthalpy ofthe brine. The energy to drive the distillation is from a combination ofdirect heating and a mechanical work input at position 0 to simulateelectrical resistive heater and the mechanical compression.Alternatively, the direct heating can also be replaced or supplementedby hot steam injection with very similar results, hence it won't bebelabored here.

For steady state conditions, the energy conservation and the second lawequations become;

$\begin{matrix}{{{Q + P} = {m_{1}\left( {h_{2} - h_{1}} \right)}}{and}} & (3) \\\begin{matrix}{{m_{1}\left( {s_{2} - s_{1}} \right)} = {\frac{Q}{T} + {\sum\limits_{l}{\overset{.}{S}}_{irrevl}}}} \\{\equiv {\frac{Q}{T} + {InternalEntropyproduction}} \geq \frac{Q}{T}}\end{matrix} & (4)\end{matrix}$

where mass flow conservation is assumed (the mass flow from the feedwater must balance the combined mass flows from the distillate and thebrine outputs).

The internal entropy production in this case comes from heat conductionlosses, resistances from fluid flows within the system, as well asenergy losses from mechanical compression and other inefficiencies.Since entropy production is merely the energy change weighted by theinverse temperature, the thermal conduction loss for a heat flow Qbetween two temperatures T₁ and T₂ is simply

$\begin{matrix}{{Q\left( {\frac{1}{T_{2}} - \frac{1}{T_{1}}} \right)} = {{Q\; \frac{T_{1} - T_{2}}{T_{1}T_{2}}} > 0.}} & (5)\end{matrix}$

The inequality arises from the fact that Q must have the same sign as(T₁-T₂) since heat can only flow from higher temperature to lowertemperature, which is the essence of the second law of thermal dynamics.Heat conduction can take place in the transverse direction to transferthe heat across the heat exchange walls, in the stream-wise direction,and also when the heat is leaked from the hot interior region to thecooler external environment. Fluid viscosity which tends to retard themovement of the fluid also contributes to the internal entropyproduction. The inherent inefficiencies of the mechanical compressor,motor, etc., also contribute to internal entropy generation. Moregenerally, by going into the continuum limit, the internal entropyproduction rate can be expressed as a positive integral which satisfiesthe variational principle, meaning that the entropy production rateintegral can be shown to be at its minimum for the solutions to the heatconduction equations and the viscous fluid dynamic equations. This wouldthen permit the use of trial functions which approximated the truesolutions of the internal system.

A variational method is widely used in physics, mathematics, computersciences, etc., to provide approximate estimation of the real dynamicssince the true solutions are difficult to obtain. Furthermore, since themagnitude of estimation errors can be predicted by the variationalmethod, the trial functions usually provide excellent results. In thecase of entropy production rate estimation, the trial function willalways give a larger value, hence it would provide a more conservativeestimate, which is desirable, since one can always be sure that the trueresults would be better than the estimates.

A performance comparison can now be made between mechanical compression(by setting Q=0) and direct heating (by setting P=0). Since the internalentropy production rate depends only on the irreversible processes whichdo not have any explicit dependencies on whether the distillationprocess is driven by direct heating or mechanical vapor compression, butinstead, depends only on such parameters as thermal conductivities, wallthickness, geometry, fluid viscosity, etc., one can expect the entropyproduction to be broadly similar assuming the mechanical power input andthe heat input are identical.

The case wherein the power input is in the form of direct heat input(for example, by using an electric heater)gives the energy conservationequation,

Q=m ₁ C _(P)(T ₂ −T ₁)  (6)

and the entropy equation,

$\begin{matrix}{\begin{matrix}{{m_{1}C_{P}{\ln \left( \frac{T_{2}}{T_{1}} \right)}} = {m_{1}C_{P}{\ln \left( {1 + \frac{Q}{m_{1}C_{P}T_{1}}} \right)}}} \\{= {\frac{Q}{T} + {{InternalEntropyproduction}.}}}\end{matrix}\quad} & (7)\end{matrix}$

For an efficient thermal distillation system, the term must be muchsmaller than 1 (noting that the temperatures are absolute temperatures),hence the logarithmic term can be approximated by keeping just the firstterm in the Taylor series expansion. Therefore,

$\begin{matrix}{Q = {\frac{T_{1}{T \cdot {InternalEntropyproduction}}}{T - T_{1}}.}} & (8)\end{matrix}$

By contrast, for mechanical compression, the expression becomes,

P=T ₁·InternalEntropyproduction  (9)

which differs from the expression for direct heating by a heat pump likefactor, or

$\begin{matrix}{P = {\left( {1 - \frac{T_{1}}{T}} \right){Q.}}} & (10)\end{matrix}$

Since the heat pump factor

$\left( {1 - \frac{T_{1}}{T}} \right)$

is much smaller than 1, especially when T₁ is close to T, the aboverelationship illustrates the thermal dynamic superiority of mechanicalcompression versus direct heating. It also shows the importance ofreducing the internal entropy production rate. This explains why it isof uppermost importance to ensure that direct latent heat exchange cantake place instead of the indirect latent heat to sensible heat transferprocess in conjunction with sensible heat to latent heat transferprocess. The latter requires very efficient heat transfer between thecondensation chamber and the evaporation chamber. Clearly having asurface to volume ratio, which lowers the surface loading factor, canlower the temperature difference to effect a large reduction of theentropy generation rate. In the present invention, the surface to volumeratio can be generally 700 m⁻¹ or greater. The reason direct heating isless efficient than mechanical compression is because of the largeentropy input in the form

$\frac{Q}{T}.$

Lowering the surface loading factor minimizes the temperature difference(more accurately, LMTD, or logarithmic mean temperature difference) bymaximizing the surface to volume ratio to be greater than 700 l/m.

The equations described above provide a way to estimate the input power(mechanical or heat) requirements from variational principle since theinternal entropy production can be approximated by the trial functionvariational method.

FIG. 2b illustrates a diagram of the present invention for waterpurification having a flooded evaporation chamber. A water purificationapparatus of the present invention 50 comprises an evaporation chamber52, a condensation chamber 54, a heat exchange wall 56 between theevaporation chamber 52 and the condensation chamber 54, a brine chamber68, a compressor 60, a demister 62, and a brine pump 64. Typically,input water is pretreated to prevent clogging and fouling of theevaporation chambers due to settling of the sediment inherent in theinput water stream as well as to reduce the scaling of the chamberwalls. Pretreatments can include screening of the input water by using ascreen filter or a sediment filter to remove larger debris or suspendedparticulates which may interfere with the main HDH processes. Finerdissolved or undissolved particulates as well as micro-organisms canalso be pretreated by filtration through a flocculation mechanism, suchas electroflocculation, biological processes such as slow sand filtersor active carbon, or by pre-chlorination to prevent the growth offouling pathogens on the plumbing and evaporation chambers. Calciumbased dissolved solids should be treated with anti-scalants orcoagulants to prevent scaling of the chamber walls and pipe-work.Pretreatment can occur during initial startups, during the resumption ofthe evaporation process after it has been momentarily halted, when theHDH process has become too unstable (e.g., caused by a rapid drop in thepeak chamber temperatures for the controller to bring it back to theoptimal state), or other situations.

The pretreated water can also be heated to a predefined temperature inorder to supply a sufficient quantity of water vapor for the vaporcompressor to work. Without the initial seed of water vapor present inthe intake port of the compressor, the condensation would not take placewith the consequent lack of latent heat transfer from the condensationchamber to the evaporation chamber and the feedback loop between theevaporation and condensation which is vital to the HDH process would nottake place. The water can be preheated by using a solar water heater(not shown), powered by solar energy or other low quality heat sources.If further heating is necessary, then a secondary heater (also, notshown), e.g., an electric heater, using another power source can beutilized to further heat the input water to the predefined temperature.Also, the secondary heater can be used to bring the temperature to ahigher level for periodic self-disinfection, e.g., when the operatingtemperature does not reach a safe zone for an extended period of time.

The pretreated input water 66 is inputted to the evaporation chamber 52,thereby flooding the evaporation chamber 52 such that the pretreatedinput water 66 is in contact with the heat exchange wall 56. Latent heatwhich is typically transferred from the condensation chamber 54 to theevaporation chamber 52 is efficiently transferred to the pretreatedinput water 66 in the evaporation chamber 52 since the pretreated inputwater 66 is entirely covering the heat exchange wall 56 on theevaporation chamber 52 side. Such submerged evaporation chamberstogether with hydrophobic condensation chambers with nominallyhorizontal (preferentially with a modest incline) heat exchange surfacesbetween the two promotes highly efficient dropwise condensation andpercolating evaporation. In dropwise condensation, the condensate formstiny beads on the heat exchange surface instead of a continuous film.These are the nucleation sites on which the droplets grow until theybecome too large to sustain themselves and the sudden rapid coalescenceand sliding down of the oversize droplets continues to sweep and clearthe surface to expose it directly to vapor molecules in the saturatedgases.

The maximum drop radius before the sudden coalescence of neighboringdroplets is called the departure radius. The departure radius for ametal surface is typically around 1-3 mm but it depends on variousfactors such as the surface temperature, surface and bulk thermalconductivity, vapor flow velocity, and the sliding mechanism. Typicallysliding occurs when the coalesced drop size increases to a point whenthe force of gravity or other clearing mechanism becomes significantlylarger than the surface tension force on the droplet. In dropwisecondensation, there is no liquid film on the surface to resist latentheat transfer leading to achievable heat transfer coefficients of overten times better than with filmwise condensation.

The sliding motion can be controlled by a combination of inclining theheat exchange surface from its approximate horizontal orientation by asuitable angle, and by adjusting the gas flow rate of the compressor aswell as its compression ratio. Stronger sliding motion increases themass flow rate of the condensate as well as reducing the departureradius which increases heat transfer. However, the increase in heattransfer coefficient typically is smaller than the increase in mass flowrate of the condensate which would necessitate an increase in thetemperature difference between the evaporator and the condenser side ofthe heat exchange surface, which reduces efficiency. Hence the inclineangle is another control parameter which can be utilized for theoptimization of the system performances.

Dropwise condensation is only realized with hydrophobic surfacematerials in direct opposition to filmwise condensation. On theevaporation side a similar effect can be achieved with percolating, orsparging, evaporation. In percolating evaporation, the evaporationchambers are flooded with liquid which is permeated with percolating gasbubbles which are recirculated from the proximal end of the condensationchamber. Percolating evaporation, contrary to dropwise condensation,prefers hydrophilic surfaces wherein the gas bubbles resulting from therecirculation of the carrier gases from the condensation chambers andthe growth of those bubbles from the continuous evaporation of theliquid into them leads to the formation of hanging bubbles right belowthe heat exchange surface. This beading of gas bubbles on the bottom ofthe heat exchange walls (the top of the evaporator surfaces) is a directreversal of the dropwise condensation, and since such reversed beadingrequires very small contact angles; thus, the evaporator surface shouldbe preferentially hydrophilic. Hanging bubbles create air bubbles sotiny that they rise in the water extremely slowly. This applies to airbubbles smaller than 0.1 mm, or so called herein micro-bubbles.

The enhanced latent heat transfer for the percolating evaporationprocess results from the growth and sudden collapse of the gas beads andsubsequent upward sliding of the oversize air beads. Since there are nogas film between the evaporator surface and the liquid to resist theheat transfer, the heat transfer coefficients can be order of magnitudelarger than the conventional evaporation chambers.

Although the contact angle of the heat exchange surfaces on theevaporator side is preferentially smaller than 90°, gas beads can stillbe formed as long as the contact angle is not close to 180°. Largercontact angles can increase the critical size of the air beads, whichreduces heat transfer efficiency. Most of the hydrophobic polymers havecontact angles no larger than 140°, hence enhanced latent heat transfercould still take place on such surfaces based on thepercolation-evaporation principle.

Incondensable gases present in the HDH process can have a large andnegative impact on the heat transfer across the heat exchange surfacesince they hinder the access of the vapor molecules to the heat exchangesurface, forcing the vapor molecules to diffuse through them. However,it is known that the heat transfer is greatly enhanced in the turbulentregime in which the transversal gas movements permit the vapor moleculesto be convected to the heat exchange surface on the condensation side.On the evaporation side, the turbulent liquid movements can likewisecause convective mixing of the liquid to overcome the poor thermalconductance of the liquid.

Although the Reynolds number for the onset of turbulent flow is around2200, which is typically larger than the Reynolds number that can beachieved in a narrow channel flow, the flow is provoked into turbulenceand micro bubble generation through micro-structured obstacles and byexternal agitations. The disclosed pulsational effect distillation (PED)of a compressor blade and the vortex forming nozzles employed torecirculate the uncondensed gases back into the flooded evaporationchambers both provide such effects. The turbulence and micro-structuredobstacles and vortex forming nuzzles can produce such micro-bubbles.

The turbulent motions of the fluids also confer additional benefits intheir abilities to scrub the heat exchange surfaces as well as non-heatexchange walls. They also directly affect the onset of the slidingmotion for dropwise condensation since they can accelerate thecoalescence of the neighboring droplets and impart the coalesceddroplets with oscillatory motions, causing them to be uprooted fromtheir micro-scaled nucleation sites. This leads to smaller departuremicro drop radius which improves heat exchange efficiency even further.

However, the presence of turbulent motions can increase the fluid dragswhich would increase the pumping pressure requirement of the compressor.Hence the tradeoff between increasing compressor power requirement andthe improved heat exchange efficiency needs to be taking intoconsideration in the system design. Note that if the exterior walls arewell-insulated, then almost all the turbulent motions would eventuallybe converted to heat, which would be utilized to increase the condensateproduction the same way direct injection of heat would do in any case,hence the overall energy efficiency would decrease only to the extentthat the turbulence induced heat generation is less efficient than themechanical energy used to drive the compressor. The relativeinefficiencies of direct heat injection versus mechanical energy inputwill be detailed in a latter section.

The evaporation chamber 52 and the brine chamber 68 can also beconnected such that the brine from the pretreated input water 66 isallowed to flow from the evaporation chamber 52 to the bottom of thebrine chamber 68 via gravity driven sedimentation. Thus, the brineconcentration at the evaporation chamber 52 is theoretically smallerthan the brine concentration at the bottom of the brine chamber 68. Asthe brine chamber 68 gets more and more concentrated with brine, theosmotic pressure can increase the brine concentration in the evaporationchamber 52. Additional levels 70 of the brine chamber 68 can be used toincrease the total path needed for the osmotic pressure to travel.

The brine pump 64 can pump the brine out of the brine chamber 68 todecrease the brine concentration, thereby alleviating any osmoticpressure. The brine pump 64 can be digitally controlled such that thebrine concentration can determine the amount of pumping needed by thebrine pump 64. The bring pump 64 can automatically set its rate ofpumping based on the brine concentration. The pumped brine water can befurther separated such that the concentrated brine and sedimentation isdiscarded, and the remainder of the pumped brine water can berecirculated to the evaporation chamber 52.

As gases are evaporated from the evaporation chamber 52, the gases arehighly saturated with the pretreated input water. The highly saturatedgases from the evaporation chamber 52 are guided through the demister 62to an inlet 76 of the compressor 60. The compressor 60 compresses thehighly saturated gases and outputs the supersaturated gases via anoutlet 78 of the compressor 60 to the condensation chamber 54. Thecompressor 60 can be digitally controlled to adjust the flow rates ofthe gases at the inlet 76 and outlet 78 of the compressor 60 and thecompression ratio for those gases as well. The disclosure furthercomprises a plurality of external micro-structured obstacles, externalagitators and vortex forming nuzzles configured to produce micro-bubblesfor introduction into the evaporation chamber.

The purpose of the demister 62 is to permit the gas bubbles to beseparated from the liquid in the evaporation chamber. Typically, thedemister comprises a fine coated or uncoated metal screen with smallenough mesh size to remove entrained liquid droplets in the form of mistin the evaporation chamber from getting into the compressor housing.Such entrained droplets are corrosive and harmful to the compressor andcould also contain organic or inorganic contaminants which could crosscontaminate the condensate on the condenser side. However, because thegas speed is typically three orders of magnitude higher than the speedof the liquid, the flow resistance exerts on the gases by the demisterscreen can lead to a non-negligible pressure drop. This reduces theefficiency of the compressor and requires more input power tocompensate, resulting in a drastic reduction of the overall energyefficiency.

Due to the lower temperature and lower pressure operations, it ispossible to replace the metal screen with a plastic demister. With theflexibility of plastic molding, the cross section of the wire mess couldbe reshaped into a longer and more streamlined shape. It is well knownthat an aerodynamically shaped cross section can be two to three orderof magnitude lower in drag coefficient than a circular shaped crosssection with the same frontal area. This would drastically reduce thepressure drop across the demister which helps to improve the overallenergy efficiency. The energy lost to the frictional pressure dropacross the demister screen is not lost. Instead, it can be convertedinto heat which adds to the heat energy input into the condensationchambers.

Since the preferred embodiment uses a flooded nearly horizontalevaporation chamber and is under the suction force of the compressor,the suction force may bring the brine liquid all the way to the entranceof the demister, hence a more effective separation of the gases and thebrine liquid is needed. The preferred embodiment for the demister is toemploy highly hydrophobic plastic materials such as Teflon for thedemister mesh which can exert a negative capillary force against thebrine liquid.

The supersaturated gases are inputted to the condensation chamber 54 toform condensed water (i.e., the product water or purified liquid) on theheat exchange wall 56. The heat exchange wall 56 is substantiallyaligned along a horizontal direction such that gravity is substantiallyperpendicular to the heat exchange wall 56 which is preferentiallyhighly hydrophobic, thus causing the condensed water to form dropwisecondensation on the heat exchange wall 56. Any remaining gases from thecondensation chamber 54 can be recirculated to the evaporation chamber52 via a path 72 to enhance evaporation and latent heat recoveryperformance through percolating evaporation. The condensation chamber 56can have an outlet 74 to allow the condensed water, i.e., product water,to flow to a storage tank (not shown) or for other usage. Thecondensation chamber 54 can also comprise a ridge 80 for furthercondensation. The ridge 80 can be slightly tilted for dripping anycondensed water onto the heat exchange wall 56. Supersaturated gases orair that remains can be recirculated to the evaporation chamber toenhance evaporation and latent heat recovery thru percolatingevaporation thus generating a 2-phase flow on the evaporation side. Onthe condensation side, the flow is always 2-phased since it containsboth the air/vapor and the condensate. The disclosure is therefore a2-phase to 2-phase heat exchange.

Since the product water and the pretreated input water 66 are on eithersides of the heat exchange wall 56, the latent heat transfer from thecondensation chamber 56 to the evaporation chamber 52 is greatlyincreased, leading to greater overall efficiency for the waterpurification apparatus 50.

To further improve the heat exchange efficiency, the bulk thermalconductivity of the substrate of the heat exchange wall should be high,the exchange surface should be as large as possible, and the wallthickness should be as small as possible. The heat exchange wall 56 canbe composed of a variety of heat conductive materials, e.g.,polypropylene, anti-corrosive resistant metal alloys, polycarbonate,and/or other materials.

Although stainless steel, copper-nickel alloy, or titanium, all haveorders of magnitude higher bulk thermal conductivity than plasticsubstrates such as polypropylene or polycarbonate, they have highwettability which are not conducive to dropwise condensation althoughthey could be treated chemically or gold coated to improve surfaceenergy. Plastic substrates such as polycarbonate and polypropylene areorders of magnitude cheaper in bulk and can be made thinner because oftheir superior corrosion resistances. And since HDH process operates ator near atmosphere pressure, the strength of the metallic substrates isnot needed. Smaller thickness of the wall can partially compensate forthe lower thermal conductance of the polymers.

In addition, the bulk conductivity of the polymeric substrates cab beenhanced with highly conductive fillers such as carbon black, carbonfibers or carbon nanotubes. Carbon additives such as carbon black canincrease the bulk thermal conductivity by as much as a factor of 4.Nano-structured carbon substrates such as carbon fibers, and even moreso, carbon nanotubes and graphene, which have thermal conductivity ashigh as pure silver, or in the case of carbon nanotube, as much as 20times higher than silver and copper, the expected increase in bulkthermal conductivity could be an order of magnitude higher. Carbon fiberand carbon nanotube additives can also drastically increase themechanical strength and stiffness of the polymer substrates, allowingeven thinner wall construction.

FIG. 3 illustrates a diagram of another embodiment of the presentinvention for water purification having an additional auxiliary steamgenerator. The water purification apparatus of the present invention 50can include an auxiliary steam generator 82 for a direct steam injectioninto the condensation chamber 54. At startup of the water purificationapparatus 50, the auxiliary steam generator 82 can be initialized topromote the condensation and evaporation process. The auxiliary steamgenerator 82 can be powered by mechanical energy, solar energy, thermalenergy, electrical energy, or other means for generating power. By usingmechanical, solar, and/or thermal, the water purification apparatus canbe very ecofriendly and leverage the surrounding natural resources.

FIG. 4 illustrates a diagram of the present invention for waterpurification having multiple channels for the evaporation chamber andcondensation chamber. A water purification of the present invention 100can be adapted by having multiple channels 102 of an evaporation chamber104 interlaced with multiple channels 106 of a condensation chamber 108.The channels 102 of the evaporation chamber 104 and the channels 106 ofthe condensation chamber 108 are interlaced such that any one channel ofthe evaporation chamber 104 is between any two channels of thecondensation chamber 108, and likewise any one channel of thecondensation chamber 108 is between any two channels of the evaporationchamber 104, except for the outer most channels. Furthermore, there is aheat exchange wall between the interfaces of each channel of theevaporation chamber 104 and each channel of the condensation chamber108, e.g., heat exchange wall 110. The channels 102 of the evaporationchamber 104 and the channels 106 of the condensation chamber 108 can besubstantially aligned along a horizontal direction such that thecondensed water will tend to pool onto the heat exchange walls due togravity. The perforated panel array as well as the tube array withspacers are all designed to guide and restrict the movements of variousfluids including inputted water, distillate, air, vapor and brine insuch a way to minimize the LMTD (logarithmic mean temperaturedifferences) between fluids which are exchanging latent heat and theunavoidable transfer to sensible heat which is kept at a minimum sincethe latent heat must first be converted to sensible heat in order toreach the inter facial boundary for evaporation to take place.

The channels 102 of the evaporation chamber 104 are connected togetherat their ends. Likewise, the channels 106 of the condensation chamber108 are connected together at their ends. A compressor 112 of the waterpurification apparatus 100 can have an inlet 114 from the evaporationchamber 104 to receive the saturated gases and an outlet 116 to thecondensation chamber 108 to output the supersaturated gases to thecondensation chamber 108. A demister 118 can be connected between to theevaporation chamber 104 and the compressor 112 to demist the saturatedgases. In addition, an air filtration device (not shown), e.g., anelector static precipitator or other electric filtering system, can beused to further filter the saturated gases for unwanted particles. Thewater purification apparatus 100 can recirculate gases from thecondensation chamber 108 to the evaporation chamber 104 via a P-trap124, or by another method or apparatus. The product water from thecondensation chamber 108 is guided to the product water storage 126. Theproduct water descends from the channels 106 of the condensation chamber108 due to gravity, or using another method, to the product waterstorage 126. The gases also descend from the channels 106 of thecondensation chamber 108 to the P-trap 124, which is further connectedto the evaporation chamber 104. Since pressure is greater in thecondensation chamber 108 than the evaporation chamber 104, the gasesfrom the condensation chamber 108 will flow through the p-trap 124 andexit into the evaporation chamber 104. Due to this higher pressure, theinput water in the evaporation chamber 104 will not backflow through thep-trap 124 to the condensation chamber 108. A micro bubble generationnozzle (not shown) or other bubble generation mechanism can also bepositioned at the end of the P-trap 124 to generate micro bubbles as thegases are guided into the evaporation chamber 104. In other words, amicro bubble generator or other micro bubble generation mechanism canalso be positioned at the end of the P-trap to generate micro bubbles asthe gases are guided into the evaporation chamber.

A brine chamber 128 can provide the input water to the evaporationchamber 104. The brine chamber 128 can have multiple levels (not shown)to increase the path taken for the osmotic pressure. Also, there can bea brine outlet 130 from the brine chamber 128 to pump the highlyconcentrated brine from the bottom of the brine chamber 128. The brinechamber 128 can also have an inlet 132 for inputting the input waterinto the brine chamber 128 and to flood the evaporation chamber 104 withthe input water.

In order to increase the amount of product water, a water purificationapparatus of the present invention can have a condensation chambercomprising multiple panels, where each panel has multiple channels. Thepanels can be interconnected at its ends and are spaced a predefineddistance away from each other. The panels are further disposed in acavity in which the cavity is filled with the input water to serve asthe evaporation chamber. Thus, the input water is flooded around thepanels, and the barrier of the panels serve as heat exchange wallsbetween the condensed water within the channels of the panels and theinput water at the exterior of the panels. Further description of thisarrangement is provided in the subsequent descriptions.

For instance, FIG. 5 illustrates a diagram of a water purificationapparatus of the present invention having multiple panels for thecondensation chamber. A water purification apparatus 150 can have a formfactor in a rectangular shape, wherein a proximal manifold 152 islocated on an upper side of the water purification apparatus 150 and adistal manifold 154 is located on a lower side of the water purificationapparatus 150. Furthermore, panels 156 of the condensation chamber canbe rectangular and mounted vertically, horizontally, or at other anglesin the water purification apparatus 150. Each of the panels 156 can havemultiple channels (not shown). Also, the panels 156 of the condensationchamber can also be rectangular in shape to match the overall formfactor of the water purification apparatus 150. An evaporation chamberof the water purification apparatus 150 can comprise of areas exteriorto the panels 156, but within the water purification apparatus 150(e.g., area 164), an upper section 158, and a lower section 160. Theseareas, the upper section 158 and the lower section 160 are connectedsuch that the input water and any gases within the input water canfreely flow between these three sections of the water purificationapparatus 150.

The channels of the panels 156 are sealed from the evaporation chamberto prevent any leakage of input water from the evaporation chamber intothe channels of the panels 156. However, dry air from the channels ofthe panels 156 are recirculated into the evaporation chamber via thedistal manifold 154. A compressor 162 can receive the highly saturatedgases from the evaporation chamber at the upper section 158 and outputsuper saturated gases to the proximal manifold 152 which connects to thechannels of the panels 156. Thus, the super saturated gases are guidedfrom the top of the channels of the panels 156 to the bottom of thechannels of the panels 156. The condensed water in the channels of thepanels 156 are pooled in the distal manifold 154, and further guided toa product water storage (not shown) or for usage.

It is understood that the above described form factor for the waterpurification apparatus 150 is only one of many form factors that can beused for implementation of the present invention. It is apparent that aperson having ordinary skill in the art can use the present invention toimplement a variety of other form factors. Therefore, these other formfactors of the present invention are also encompassed by the presentinvention.

FIG. 6 illustrates a diagram of a distal manifold of the waterpurification apparatus of the present invention. The distal manifold 154comprises a p-trap 172, a slit 174, drain holes 176, mounting pegs 178,and a product water guide 180. The p-trap 172 recirculates the gasesfrom the panels 156 of the condensation chamber to the evaporationchamber via the slit 174. The slit can have a bubble generationapparatus (not shown) for promoting the generation of bubbles into theevaporation chamber. The drain holes 176 connect the panels 156 to theproduct water guide 180 to allow the product water, condensed in thepanels 156, to be collected and then guided to the product water storagevia the product water guide 180. The mounting pegs 178 allow for thepanels 156 to be mounted and secured within the water purificationapparatus.

FIG. 7 illustrates a diagram of a proximal manifold of the waterpurification apparatus of the present invention. The proximal manifold152 of the present invention comprises an evaporator inlet 182,saturated gas outlets 184, and mounting pegs 186. The evaporator inlet182 collects the highly saturated gases from the evaporation chamber,and then guides those gases to an inlet of the compressor of the waterpurification apparatus of the present invention. The compressorcompresses those highly saturated gases and outputs the super saturatedgases to the panels 156 via the saturated gas outlets 184. The mountingpegs 186 are used to mount and secure the panels 150. FIG. 8 illustratesa perspective view of a water purification apparatus of the presentinvention. As stated above, a water purification apparatus 200 can havea rectangular form factor. A perspective view of the water purificationapparatus illustrates such form factor.

FIG. 9 illustrates a top view of a single panel of the present inventionhaving several perforations through the even numbered channels of thepanel. Each panel can have a plurality of channels, e.g., channels 1-18.The channels can have one or more cross sectional shapes, includingrectangular, elliptical, or other shapes. In this example, the channelsare rectangular in shape, such that a top view of the channels isrectangular. Channels 1, 3, 5, 7, 9, 11, 13, 15, and 17 aresubstantially impermeable to exterior liquids and/or gases, whilechannels 2, 4, 6, 8, 10, 12, 14, 16, and 18 have perforations that linkthe interior of those channels to exterior liquids and/or gases presentat the exterior of the panel. Thus, the perforated channels 2, 4, 6, 8,10, 12, 14, 16, and 18 are flooded with liquids and/or gases present atthe exterior of the panel. The ends of perforated channels 2, 4, 6, 8,10, 12, 14, 16, and 18 are sealed to prevent any outside liquids and/orgases from entering into the condensation chamber and any of thenon-perforated channels. In essence, the non-perforated channels serveas the condensation chamber and the perforated channels augment theevaporation chamber.

Typically, the channels of the panel are substantially impermeable fromgases and/or liquids leaking into the channels from the exterior of thepanel. However, to improve thermodynamic processes, every other channelalong the panel can have perforations that are cut into the channel thatallow the perforated channel to be flooded with any exterior liquidsand/or gases that surround the panel. For instance, if liquid surroundsthe panel, the liquid can surround the non-perforated channels from allsides since the adjacent channels of the panel are perforated.

The non-perforated channels have highly saturated gases that flow fromone side of the non-perforated channels to the other side of thenon-perforated channels, as detailed above. The exterior of the panel isin contact with the liquid in the evaporation chamber. Thus, the wallsof panel that form the non-perforated channels act as heat exchangewalls between the condensation chamber and the evaporation chamber.Gases that are recirculated into the evaporation chamber can also travelthrough the flooded area, thereby colliding and stumbling through thenetwork of perforations and panels. Since the paths of the gases areincreased, the recirculated gases can be further saturated before beingcollected by an inlet of the compressor of the water purification.

FIG. 10 illustrates a top view of another panel of the present inventionhaving several perforations through the odd numbered channels of thepanel. Channels 1, 3, 5, 7, 9, 11, 13, 15, and 17 have perforations. Theperforations allow for those perforated channels 1, 3, 5, 7, 9, 11, 13,15, and 17 to be flooded with liquid and/or gases present at theexterior of the panel. Channels 2, 4, 6, 8, 10, 12, 14, 16, and 18 aresealed from the exterior of the panel to prevent leakage from theexterior of the panel into the non-perforated channels 2, 4, 6, 8, 10,12, 14, 16, and 18. The ends of channels 1, 3, 5, 7, 9, 11, 13, 15, and17 are sealed to prevent any outside liquid and/or gases from enteringthe condensation chamber and any of the non-perforated channels of thepanel.

The condensation chamber can have an array of panels (as illustrated inFIG. 5), where each panel has multiple channels. As previouslydiscussed, certain channels of each panel can have perforations, e.g.,at every other channel along the panel, such that any liquid and/orgases exterior to the panel is substantially prevented from leaking intothe non-perforated channels. The perforated channels from one panel andan adjacent panel can be offset such that there are no directperpendicular lines that can cross through one perforated channel of afirst panel to another perforated channel of a second adjacent panel.The purpose is to increase the path that any gases may take from one endof the evaporation chamber to the other end of the evaporation chamberby having to cross through the perforated channels of the condensationchamber.

Therefore, several panels can be arranged in an array to form parts ofthe condensation chamber, where a first panel has perforated channels onthe even numbered channels of that panel, a second panel has perforatedchannels on the odd numbered channels of that panel, a third panel hasperforated channels on the even numbered channels of that panel, and soon and so forth, such that the perforations are offset from the any twoadjacent panels to increase the path any gases may need to take from oneside of the evaporation chamber to the other side of the evaporationchamber.

The perforations can also be of varying lengths. Furthermore, theperforations of a first panel may be also offset from the perforationsof a third panel to further increase the length that any recirculatedgases must travel through the input water in the evaporation chamber.

FIG. 11 illustrates a zoomed-in perspective view of a panel of thepresent invention having several perforations through some of thechannels and spacers. A panel 260 of the present invention can compriseof channels that are perforated at every other channel and have a spacer262 to separate any two adjacent panels from each other.

FIG. 12 illustrates a zoomed-in perspective view of several panels ofthe present invention. Several panels 280-286 are disposed adjacent toeach other to form a portion of the condensation chamber. Each of thepanels 280-286 has perforated channels. Furthermore, spacers 290-296 aredisposed between the panels 280-286 for structural integrity.

FIG. 13 illustrates a grouping of tubes to form a condensation chamberof the present invention. In an embodiment of the present invention, aplurality of tubes, e.g., tubes 300-312, can be grouped together to formchannels of a condensation chamber of the present invention. The wallsof the tubes can serve as the heat exchange walls between the condensingliquid-saturated gases within the tubes and the input liquid of theevaporation chamber that is exterior to the tubes. Spacers, e.g.,spacers 320-326, can be positioned around a tube such that there is agap between any two adjacent tubes when the adjacent tubes are groupedtogether. When the tubes are submerged within the evaporation chamber,gases and the input water in the evaporation chamber flood the exteriorof the tubes, i.e., the space in between any two adjacent tubes, andhence surround each of the tubes.

Preferably, the volume of the input liquid in the evaporation chamber isequal to the inner volume of the tubes of the condensation chamber. Dueto the dense packing of the tubes within the evaporation chamber, thetotal surface area of the heat exchange walls of the tubes are greatlyincreased. For instance, a group of tubes that are grouped togetherwithin a volume of one foot by one foot by two feet can have a totalsurface area for the heat exchange walls of around 700 sq. feet or more.Thus, generally speaking, the packing density of the present inventioncan rival some reverse osmosis filtration systems.

The tubes can be grouped together in a variety of configurations tomaximize the total surface area of the heat exchange walls and/or tomaximize other considerations for the evaporation chamber and thecondensation chamber. For instance, preferably, the tubes are packed ina hexagonal pattern, where the radial center for each of the tubes isequidistant from the radial centers of adjacent tubes. For tubes withinthe boundary of the tube grouping, i.e., an inner tube), the inner tubewill have six adjacent tubes. For example, a tube 330 is an interiortube and has six adjacent tubes surrounding the tube 330.

Since the tubes are submerged within the evaporation chamber, the endsof the tubes are sealed so that the input liquid from the evaporationchamber does not leak into the tubes of the condensation chamber.Multiple methods for sealing the ends of the tubes from the evaporationchamber can be implemented. For instance, a gasket assembly can be usedat the ends of the tubes to seal the inside of the tubes from theevaporation chamber. The gasket assembly can route saturated gases intothe interior of the tubes while providing a tight seal to prevent theinput liquid in the evaporation chamber from leaking into the tubes. Thegasket assembly will become more apparent in the following descriptions.

FIG. 14 illustrates a rectangular tube cartridge for the condensationchamber of the present invention. In various embodiments of the presentinvention, the tubes of a condensation chamber of the present can begrouped together in a rectangular tube cartridge 358. The ends of thetubes of the rectangular tube cartridge 358 are sealed by an end cap 360and 362. End caps 360 and 362 of the rectangular tube cartridge 358 canbe inserted into companion assemblies (not shown) of a waterpurification apparatus of the present invention to form a gasketassembly. Once the end caps 360 and 362 are fitted to the companionassembly, the exterior of the tubes and the interior of the tubes aresealed from each other. Hence, input liquid within the evaporationchamber that is exterior to the tubes cannot leak into the interior ofthe tubes. Also, the rectangular tube cartridge 358 and the gasketassembly are detachable from a respective water purification apparatusshould the need arise, e.g. if the tubes need to be cleaned or replaced.Additionally, the tube cartridge can also be shaped in a variety ofshapes, e.g., an elliptical shape, a circular shape, a trapezoidalshape, etc., to fit into a water purification apparatus of the presentinvention.

FIG. 15 illustrates a tube of the condensation chamber of the presentinvention having a spacer. The tubes of the condensation chamber of thepresent invention can have spacers around the exterior of the tubes. Thespacers serve to physically separate any two adjacent tubes from eachother when the tubes are grouped together. Also, the spacers serve tocapture gas bubbles within the evaporation chamber that travel near thetubes. Once captured, the gas bubbles are driven along the spacer,thereby slowing down the gas bubbles from reaching an end of theevaporation chamber.

A spacer of a tube can have one or more fins that extend from one end ofthe tube to the other end of the tube. For instance, a tube 370 can havea spacer 372. The spacer 372 is a single fin that extends around theexterior of the tube 370 from one end to the other end in a spiral. Thespacer 370 can also have a lip or edge at the end of the fin to capturegas bubbles traveling near the tube 370.

In alternative embodiments, the spacer of the tube 370 can have multiplefins (not shown) that extend around the exterior of the tube 370 in aspiral. Furthermore, instead of fins, the spacer of the tube 370 can berings that protrude from the tube 370 at various locations along thelength of the tube 370 (e.g., as illustrated in FIG. 13).

FIG. 16a illustrates a zoomed-in view for an end of a tube of thecondensation chamber of the present invention. The spacer 372 of thetube 370 can have an edge 374 on the distal side from the tube 370 tocapture gas bubbles. The edge 374 can be set at varying degrees relativeto the rest of the spacer 372. The edge 374 can also extend with thespacer 372 along the length of the tube 370. Additionally, the edge 374can be tapered at certain locations along the tube 370 to allow for thetrapped gas bubbles to escape the spacer 372.

FIGS. 16b-16c illustrate various cross sectional shapes for a spacer ofa tube of the present invention. The edge of a spacer of the presentinvention can have varying shapes. For instance, a spacer 380 can have acurved edge 382 that extends to both sides (or either side) of thespacer 380. Also, the spacer 384 can have a flat edge 386 that extendsto both sides (or either side) of the spacer 384. Based on the presentdisclosure, it is apparent to a person having ordinary skill in the artthat other edge shapes can also be used in conjunction with the presentinvention. Therefore, it is understood that the present invention alsoteaches those various edge shapes as well.

FIG. 17 illustrates a diagram of another embodiment of the presentinvention for water purification having a rectangular tube cartridge. Awater purification apparatus of the present invention 400 comprises, anevaporation chamber 402, a condensation chamber 404 having a rectangulartube cartridge 406, a compressor 408, a brine pump 410 and a productwater reservoir 412. The evaporation chamber 402 is flooded with inputliquid such that the rectangular tube cartridge 406 is submerged withinthe input liquid. The rectangular tube cartridge 406 has a first endcap414 and a second endcap 416. The endcaps 414 and 416 are fitted into agasket assembly of the water purification apparatus 400 to form a sealto prevent the input liquid from leaking into the interior of the tubesof the rectangular tube cartridge 406.

A hood 418 routes the saturated gases from the evaporation chamber 402to the compressor 408. The compressor 408 can then pressurize thesaturated gases and output supersaturated gases to the tubes of therectangular rube cartridge 406. The supersaturated gases travel throughthe endcap 414 to the other side of the tubes, i.e., to the side havingthe end cap 416. The compressor 408 can be located within the thermalboundaries of the water purification apparatus 400 to transfer itsmechanical energy to the water purification apparatus 400. For instance,the compressor 408 can be submerged into the evaporation chamber 402(not shown) such that the mechanical energy from the compressor 408 istransferred to heat the input water. In addition, the vibrations of thecompressor 408 also aid in vibrating the water purification apparatus400 to unlodge various brine and other impurities from the spacers andtubes of the condensation chamber 404.

As the supersaturated gases condense within the tubes, the product watercan be drained into the product water reservoir 412. The tubes of thecondensation chamber 404 can be slightly tilted at an angle such thatgravity can pull the product water into the product water reservoir 412below. The dry air from the tubes can be routed to the bottom of theevaporation chamber 402 or the bottom of the condensation chamber 404.When the brine concentration reaches a predefined level, the brine pump410 can be activated to start pumping the brine from the bottom of theevaporation chamber 402.

It is apparent to a person having ordinary skill in the art that otherfeatures disclosed in the present invention can be used in conjunctionwith the water purification apparatus 400. Therefore, it is understoodthat those feature can also be applied to this embodiment of the presentinvention.

FIG. 18 illustrates a perspective view of a demister of the presentinvention. A demister 420 of the present invention can have two layers422-424 of aerodynamic fins coupled onto each other, e.g., stacked ontoeach other, glued together, molded together, or using othermanufacturing techniques to form the two layers. The first layer 422 cancomprise of a plurality of aerodynamic fins made of hydrophobic materialto prevent liquid from wetting the surface of the fins. The fins of thefirst layer 422 can be substantially aligned in parallel. The secondlayer 424 can comprise a plurality of aerodynamic finds made ofhydrophilic material to promote wetting at the surface of these fins.The fins of the second layer 424 can also be substantially aligned inparallel. The fins of the first layer 422 and the fins of the secondlayer 424 can be positioned substantially perpendicular to each other.Other layers of fins can be added as necessary or designed.

As gasses and liquid boils from the evaporation chamber, the emittedliquid will tend to come in contact with the first layer 422, but sincethe first layer is hydrophobic the liquid will break apart into smallerbeads. If the smaller beads continue upward, the second layer 424 whichis hydrophilic will promote wetting of those beads on the second layer424, rather than allowing the beads to escape onward, e.g., to thecompressor. Once the beads of the input water gather on the second layer424, gravity will work to pull the beads of input water back into theevaporation chamber.

FIG. 19 illustrates an additional perspective view of a demister of thepresent invention. Preferably, a separation distance between the centersof any two adjacent fins of a layer can be a fifth of the width of eachof the fins. For instance, the separation 440, between the centers oftwo adjacent fins of the same layer is ⅕ the length of the width 442 ofthe fins of that layer. Other distancing arrangements are apparent to aperson having ordinary skill in the art based upon the presentdisclosure.

FIG. 20 illustrates an aerodynamic fin of a demister of the presentinvention. An aerodynamic fin 460 of a demister can have an aerodynamicdesign to allow for gasses to pass through the fin.

As apparent from the above disclosure, the present invention aims topresent simple, modular, and affordable water purification methods,apparatuses, and systems that are able to be adapted to localconditions, using less power and even possibly naturally availableenergy sources, like solar and wind power. The present invention can beself-monitoring and is field maintainable with minimal training and doesnot need the use of consumables for maintaining optimum systemperformance.

The present invention can also utilize sensors located inside the waterpurification apparatus to monitor the temperature and moisture at thevarious stages to optimize efficiency and product water output. Forinstance, airflow in the condensation chamber can be controlled tomaintain the correct differential to encourage maximum condensation.

A control system of the water purification apparatus can continuouslymonitor the water purification apparatus, e.g., for controlling inputwater pre-heating, energy management (including solar and wind powergeneration), controlling the temperature at various stages to maintainsafe temperatures to prevent mold formation, provide a graphical userinterface via a handheld device—wired/wireless and be able to log allsystem operations, self-maintenance: monitor the quality of the input,drain, and product water several times per unit of time, detect when theefficiency of the system is going down—possibly caused by scaling andthereby initiating a self-flush/cleaning cycle, and monitoring thesystem temperature on a continuing basis to ensure that the systemoperates in a safe temperature zone and does not become a breedingground for dangerous bacteria/mold—by controlling the electric heater toself-sanitize the system periodically. Additionally, the control systemcan monitor the TDS level.

Perhaps even more importantly, the control system can be employed tooptimize the operation for maximum energy efficiency through theprinciple of minimum entropy production. In HDH devices, entropyproductions are predominantly the results of heat transfer through atemperature difference between the source and sink. Although the entropyproduction processes are internal to the system, its magnitude can beestimated by monitoring the heat input and output rate as well as thetemperature and mass flow rate of each external port in real time. Oncethe total entropy production rates are obtained, a MIMO(multiple-input/multiple-output) adaptive control algorithm can beemployed to keep the entropy production near the minimum level by usingthe entropy production as the objective function for the controloptimization since the operation state which is most energy efficient isalso the one with least entropy production and vice versa.Alternatively, the objective could be chosen to be the unit energy costrather than entropy productions to take into account the varying costsof different energy resources. Thus it would be possible to employ amixture of mechanical compression and direct heating through theauxiliary steam generation to achieve the lowest total energy cost.

The primary energy input for the Pulse Effect Distillation (PED) processis mechanical gas compression. Although such a heat exchange maintains atemperature gradient which is an intrinsic characteristic of acounter-flow heat exchanger, the specific PED distillation processmimics an ideal thermodynamically reversible process and indeedapproaches that ideal limit when cross-wall and flow-oriented thermalresistances are zero and infinity, respectively.

As such, the energy efficiency of PED based water purification processdepends entirely on how close the PED process can imitate the idealthermodynamic reversible process, which in turn depends on theminimization of the specific rate of increase in the entropy flowsbetween the input fluid (source water) and the output fluids (productwater and brine). The sources of such entropy rate increases areprimarily the direct heat input which introduces entropy inflow. Notethat mechanical energy input introduces no increase in entropy inflowand internal entropy production rates. Internal entropy productionmainly comes from cross wall and parallel thermal transfers as well asfrom viscous and turbulent resistance to fluid flows for both water andgases (air and water vapor).

For inadequately insulated PED enclosures, the inevitable heatdissipation to the external environment also introduces additionalentropy production with attendant loss of energy efficiency. Thedisclosed direct latent heat exchange or 2-phase to 2-phase heatexchange, counter-flow heat exchange design is fully reversible for allintents and purposes. A) Both sides of the common wall contain a 2-phaseflow and the surface to volume ratio is large, at least 600 m-1 usingatmospheric pressure and evaporation-condensation. The direct latentheat exchange is of uppermost importance to ensure a direct heatexchange.

Supersaturated gases are formed from the mechanical vapor compressionprocess. Pure water vapor in industrial distillation/desalination plantsdoes not become supersaturated since there is no air involved as theseare mostly vacuum distillation processes. Saturated vapor means thevapor that is contained in air has reached saturation pressure.Supersaturation means after compression, the vapor within air becomesgreater than the saturation pressure. This is characteristic of ameta-stable state since super saturated vapor condenses as soon as thelatent heat contained within it can be released by heat exchange to theevaporation side.

The perforated panel array as well as the tube array with spacers areall designed to guide and restrict the movements of various fluidsincluding inputted water, distillate, air, vapor and brine in such a wayto minimize the LMTD (logarithmic mean temperature differences) betweenfluids which are exchanging latent heat and the unavoidable transfer tosensible heat which is kept at a minimum since the latent heat mustfirst be converted to sensible heat in order to reach the inter facialboundary for evaporation to take place.

The resulting temperature drop along the heat conducting path reducesthe temperature at which the evaporation takes place. With micro-bubblesclose to the heat exchange walls, the heat conducting path is eithernonexistent or is extremely small, so the effect of temperature drop isminimized or avoided. The LMTD minimization is accomplished by aligningthe input flow of dirty water and air micro-bubbles preferably along thechannel for panel arrays or along a direction of a hexagonal tube arrayso the flow is in the direction of increasing temperature from secondend to the first end. The cooler input water is released into the secondend and the vapor generated via evaporation, together with air itself,exit the first end to enter the compressor inlet where the temperaturereaches its highest point. The compressed and supersaturated air exitsthe compressor and enters the second end of the condensation channelsvia tubes with a slight increase in temperature due to compression, andthe supersaturated vapor (air or water that is supersaturated) travelsdown the condensation channels and proceeds to condense along thechannel walls.

The supersaturation state of the air/vapor is maintained since the gasmixture experiences a steady decrease in temperature once the vaporcondenses and becomes merely saturated by traveling downward toward thesecond end. The colder wall temperature again brings it back to thesuper-saturated state, much like how rain shower is generated by thecollision of the warm front and the cold front. Therefore, theevaporator fluid flows and the condenser fluid flows are in oppositedirections while their respective heat are being exchanged, whichprecisely corresponds to the optimum counter-flow heat exchange design!

Embodiments of the disclosure include a surface to volume ratio at least600 m-1, a direct latent heat exchange or 2-phase to 2-phase heatexchange, a counter-flow heat exchange design, bulk/percolatingimmersion evaporation and close-loop air recirculation, as well asatmospheric pressure distillation are all included. Explanation ofmicro-bubble generation includes limiting the bubble sizes to meanbubble size at the bubble generation site should be less than 0.4 mm andgreater than 500 nanometers, but preferably less than 0.05 mm butgreater than 1 micron since nano-bubbles cost energy to make and riseway too slowly!

B) Supersaturated gases are explicitly written in the present technicaldisclosure. Note that compressing a saturated air (air+vapor)immediately leads to the wet air being in a supersaturated state fromfundamental thermodynamics.

Counter-flow and cross-flow architectures are disclosed. Micro-bubblegenerator for air injection is also disclosed. A“micro-bubble-generator” includes limitations specifying that a meanbubble size should be less than 0.5 mm or so, and preferentially lessthan 0.1 mm, or something similar.

References may use a sparg tube to create vapor bubbles but does notconstitute any equivalency to our bubble generator. A sparg tube has asimple array of orifices which would be unable to generate bubbles ofextremely small sizes. According to laws of physics of micro/nano bubblegeneration, even for extremely small orifice diameters, the mean bubblesize does not depend on the diameter of the orifices as long as they aresmaller than a few tenth of a millimeters, but rather it is determinedalmost entirely on the balance between the surface tension of the waterwhich acts to keep the bubble attached and the detachment forces, mostlythe buoyancy force of the air bubble which tries to free the bubble fromthe restraining force of surface tension and other forces, if present.The bubble will detach only when the detaching forces are larger thanthe surface tension, and that determines the sizes of the free bubbles.

Sparg tube teachings on the other hand, do not generate miniaturebubbles, but instead only average size bubbles typically having a meandiameter greater than 3 mm. It should also be noted that only microbubbles with a diameter of less than 0.1 mm could stay small for a longtime since those tiny air bubbles would acquire surface charges whichgives rise to the zeta potential widely used in colloidal suspensionscience. Since like charges repel, such miniature bubbles would notcollide and therefore can stay small.

By contrast, vapor bubbles collide often and by so doing, can grow veryrapidly to large bubbles, not to mention that vapor bubbles areinherently unstable because they require a delicate balance between thevapor pressure and the local water pressure which strongly depends onthe depth of water. Any pressure imbalance, such as when the vaporpressure is lower than the surrounding water pressure, would cause thevapor bubble to implode in the form of violent cavitation. Priorreferences count on such cavitation events similar to ones generated bystrong ultrasound or rapidly revolving propeller blades in water toremove the tough scaling deposited on the tube walls. However, eventhough some references using vapor bubbles in a desalination device,resultant bubbles are used to descale via a compressed vapor to do so,vapor that could be used to increase the condensable vapor.

Embodiments of the disclosure use stable microscopic air bubbles tocollect vapor and to facilitate bulk evaporation since the extremelylarge surface area relative to the volume of such air bubbles providelarge interfacial boundaries between air and water for evaporation totake place even when the water temperature is nowhere near the boilingpoint. The air in air bubbles stabilize the vapor that is containedwithin, since if the vapor pressure, which is always the saturationvapor pressure which is true for any enclosed environment, is lower thanthe water pressure, the air within can expand/contract to adjust itspartial pressure to match any pressure deficit thereof.

In embodiments of the disclosure, the very manner of operating a devicehas a strong bearing in terms of its physical characteristics, and inmany cases, different ways of operating a device would affect its powerefficiency, among other things. As an example, consider the case of afour-port heat exchanger where two different fluids are exchanging heat.In the case where the inlet ports of both fluids are on the same side,and the outlet ports of both fluids are on the other same side, then thedevice is considered to be an inferior co-flow heat exchanger in termsof heat exchange efficiency vs that of a counter-flow heat exchanger.The same device operates as a counter-flow heat exchanger just byreassigning the ports without ever having to make any change in thephysical construction. Co-flow heat exchangers and non-counter-flow heatexchangers are considered as a basis for the improvements of the presentdisclosure.

Accounting for the latent heat from condensation transferred to sensibleheat by raising the temperature, transferring latent heat between theinput liquid and the channels via the channel walls occurs because thelatent heat is transferred between the input liquid and the channelseven if indirectly! High degrees of energy inefficiencies occur if thelatent heat transfer is not direct.

According to processes contained in the disclosure, any time a heattransfer takes place between two items with a temperature difference,entropy production lowers the energy efficiency of the system becausethe transfer process is no longer thermodynamically reversible withoutcost. The greater the temperature difference, the larger the entropyproduction. This is precisely the reason why counter-flow heat exchangeis the preferred process when energy efficiency is the main concernsince counter-flow exchange process provides the smallest LMTD, orlogarithmic mean temperature difference, which is equivalent to minimumentropy production.

Embodiments transfer the latent heat to sensible heat first, thetemperature difference is raised quite drastically, since the heat fluxmust travel thru water in order to reach the interfacial regioncomprising both the air-water boundary and its immediate vicinity, heatis absorbed by the evaporation process taking place there. Thecorresponding temperature drop means that the heat flux would beabsorbed at a point or in a tiny region where the water temperature islowered by conduction thru water. This is the same thing as exchangingheat thru a thick wall or a thermal insulator. Water is a mild insulatorbecause it does not conduct heat too well.

Through the micro-bubbles or very, very small bubbles of the disclosurethe latent heat is transferred to the nearest interfacial surface of abubble. The process is still not completely direct since the latent heatflux must travel thru the tube wall as well as the water that sitsbetween the nearest wall surface and the interfacial surface. So ineffect, it is still an indirect process since there are temperaturedrops between the point where the condensation takes place and the pointwhere evaporation actually occurs. However, as long as the wallthickness is small and the bubble density is high and fairly uniformlydistributed, the sensible heat exchange portion is minimized. So fromthat point of view, the disclosure is a direct latent heat exchangeprocess.

In other embodiments, all heat conducting walls are either thin-wallmetals or thin-wall plastics designed to provide a largesurface-to-volume-ratio for the heat exchange channels to maximize waterproduction in a limited space. The disclosure keeps the pressuredifferences between interior or exterior compartments as small aspossible, which requires atmospheric operation. Further, owing to thedisclosed close-loop air recirculation to introduce micro-air bubbles,an exchange of the recirculating air with outside air periodicallymaintains pressure balance as well as to replace or replenish air. Withatmospheric operation, the disclosure performs exchange without theadded cost of a blower/compressor. Therefore, atmospheric operation ispart to the disclosed operation and the electrostatic precipitator andothers are employed to facilitate such air exchange to avoid introducingdirty air into the disclosed system. None of these limitations arerequired in any reference design.

However, reference designs require strong walls for tube and tankconstruction which sacrifice heat exchange efficiencies since thosewalls need to be strong and thick metals which can withstand the largepressure difference that exist. So fundamentally, two distinct devicesare distinguished unlike the case with counter-flow vs other flow heatexchangers since these exchangers may be configured with similarphysical construction, where the port assignments further distinguishthem.

In an embodiment, micro bubbles contain recirculated air from thecondensation channels after condensation has taken place, meaning therecirculated air is collected at the bottom ends of the condensationchannels where most of the vapor containing thereof has alreadycondensed and the bubbles are primarily air bubbles of sufficientlysmall sizes. Otherwise a portion of the saturated gas is recirculatedrather than pure compressed vapor, not saturated gases. Saturation isonly meaningful when it refers to the vapor of the second liquid mixingwith the first gas, or gases. Therefore, the air is saturated with watervapor, or equivalently that the relative humidity of the air is 100%.

Regarding non dirty water recirculation, the input water may be locatedabove a filter so that the impure water flows over the filter. Inputwater enters a boiler above a titanium wool filter. The water that fallson the wool filter partially evaporates thru a second filter. The waterthat is not evaporated passes thru the filter to the brine section. Themain filter is wet all the time and removes brine particles caught inthe filter back to brine section. The secondary filter is supposed tocatch any brine particles and force them back thru the filter to thebrine section.

The most basic precipitator contains a row of thin vertical wires,followed by a stack of large flat metal plates oriented vertically, withthe plates typically spaced about 1 cm to 18 cm apart, depending on theapplication. The air stream flows horizontally through the spacesbetween the wires, and then passes through the stack of plates. Anegative voltage of several thousand volts is applied between wire andplate. If the applied voltage is high enough, an electric coronadischarge ionizes the air around the electrodes, which then ionizes theparticles in the air stream. The ionized particles, due to theelectrostatic force, are diverted towards the grounded plates. Particlesbuild up on the collection plates and are removed from the air stream.

Therefore, air stream flows horizontally thru the space between thevertical wires and the stack of metal plates with a voltage of thousandsof volts to create a CORONA DISCHARGE! This distinguishes over filtersmounted horizontally and the water/vapor/brine particles that travelvertically thru them. Based on horizontal flow, brines particle won't becaught and even if they did, they would not fall back to brine section.Also, water and brine particles and brine droplets are included sincenon-dissolved solids within input water can't really be separated fromthe input water and mixed with vapor during the evaporation process.

Instead, a second filter simply performs like a regular demister whichremoves all the entrained droplets and droplets created by splashingduring the evaporation process or during initial introduction of inputwater thru input or during the falling of the input water thru the firstfilter. A demister is a must in almost all boilers/evaporators sinceentrained brine droplets and droplets that get carried along by the flowof the vapor or other gas is unavoidable. As such those brine particlesare highly conducting contaminated drops of water which wouldimmediately short the high voltage gaps between the wires and theplates! The corona discharge is particularly strong owing to thepresence of water droplets. The discharge always takes the shortestpath, which means it would jump from droplet to droplet, ionizing themat the same time. Once a plasma laden path is formed, the ions rich pathfurther guide the electricity to travel in this highly conductive pathand short the wire/plate terminals out.

C) Therefore, the disclosed Pulse Effect Distillation (PED) andcounter-flow designs are distinguished over cross-flow designs asexplained and shown above and in the drawings in support of the claimswhich immediately follow herein.

While the present invention has been described with reference to certainpreferred embodiments or methods, it is to be understood that thepresent invention is not limited to such specific embodiments ormethods. Rather, it is the inventor's contention that the invention beunderstood and construed in its broadest meaning as reflected by thefollowing claims. Thus, these claims are to be understood asincorporating not only the preferred apparatuses, methods, and systemsdescribed herein, but all those other and further alterations andmodifications as would be apparent to those of ordinary skilled in theart.

What is claimed is:
 1. An apparatus for generating purified liquid froman input liquid, comprising, a condensation chamber having multipleinternal partition channels disposed in the input liquid, wherein themultiple internal partition channels comprise a first group of channelsand a second group of channels, wherein the second group of channels areperforated to allow the input liquid to flood the second group ofchannels, wherein the channels of the first group and the second groupof channels are interlaced such that each one of the channels of thefirst group is surrounded by the input liquid, and the purified liquidis outputted at a second end of the first group of the channels; anevaporation chamber flooded with the input liquid and wherein theevaporation chamber generates saturated gases and comprises a sharedwall with the condensation chamber and wherein the evaporation chamberis configured to generate evaporation cavities and condensation cavitieson respective sides of the shared wall for a 2-phase counter flow of aliquid phase component and a gaseous phase component in composite flowsfor a 2-phase to 2-phase direct latent heat exchange; a compressoroperatively connected to the evaporation chamber to receive saturatedgases from the evaporation chamber, wherein the compressor pressurizesthe saturated gases to generate supersaturated gases, wherein thecompressor is operatively connected to the first group of channels ofthe condensation chamber, wherein the compressor outputs thesupersaturated gases to the first group of channels of the condensationchamber via a first end of the first group of the channels of thecondensation chamber; a bubble generator configured to recirculate aportion of the liquid and gases of the condensation chamber and theevaporation chamber, wherein the bubble generator is configured topermeate the input liquid with percolating gas bubbles which are adaptedto form hanging micro bubbles beading right below a heat exchangesurface of the evaporator chamber; and a P-trap channel comprising afirst end operatively connected the condensation chamber and a secondend operatively connected to the bubble generator disposed in theevaporation chamber, wherein the P-trap channel and the bubble generatorare configured to recirculate a portion of the saturated gasses from thecondensation chamber to the evaporation chamber.
 2. The apparatus ofclaim 1 wherein the walls of the channels are heat exchange walls andwherein latent heat is transferred between the input liquid and thechannels via the walls of the channels and a beading of the gas bubbleson a bottom of the heat exchange walls.
 3. The apparatus of claim 1further comprising a surface to volume ratio at least 600 l/m andpreferably greater than 700 l/m on the shared wall to lower the surfaceloading factor and minimize the temperature difference there between. 4.The apparatus of claim 1 wherein the condensation chamber, thecondensation chamber, the compressor, the bubble generator and theP-trap channel comprise a closed-air closed-water HDH system.
 5. Theapparatus of claim 1 wherein the evaporation chamber and thecondensation chamber are configured for a bulk/percolating immersionevaporation as well as atmospheric pressure distillation via the 2-phasecounter-flow design without the added cost of a blower/compressor thoughan electrostatic precipitator is employed to facilitate such airexchange to avoid introducing dirty air into the disclosed system. 6.The apparatus of claim 1 further comprising a plurality of externalmicro-structured obstacles, external agitators and external vortexforming nuzzles configured to produce micro-bubbles introduced into theevaporation chamber.
 7. The apparatus of claim 1 the bubble generatorand external micro bubble generation mechanisms are positioned at theend of the P-trap to generate micro bubbles as the gases are guided intothe evaporation chamber.
 8. The apparatus of claim 1 further comprisinga panel array alignment of input dirty water and air micro-bubbles alonga direction of a hexagonal tube array so the flow is in the direction ofincreasing temperature from a second end to the a first end and coolerinput water is released into the second end and the vapor generated viaevaporation, together with air itself, exit the first end to enter aninlet of the compressor where the temperature reaches its highest point.9. The apparatus of claim 1, wherein the evaporator fluid flows and thecondenser fluid flows of liquid condensate and air/vapor are configuredto flow in opposite directions while their respective heat are beingexchanged comprise the 2-phase counter-flow design.
 10. The apparatus ofclaim 1 wherein the apparatus is operated as a four-port counter-flowheat exchanger where the two different fluids are exchanging heat basedon the inlet ports of both fluids being configured on opposite sides andthe outlet ports of both fluids are also configured on opposite sides.11. The apparatus of claim 1, wherein the micro bubbles generated by thebubble generator are a mean 0.4 mm, but preferably less than 0.05 mm andgreater than 1 micron.
 12. The apparatus of claim 1, wherein a pressurein the condensation chamber exceeds a pressure in the evaporationchamber.
 13. The apparatus of claim 1 further comprising a sedimentchamber, wherein the sediment chamber is operatively connected to theevaporation chamber for allowing heavier particles in the liquid tosettle in the sediment chamber.
 14. The apparatus of claim 1 furthercomprising percolating evaporation on the evaporation chamber side viarecirculating supersaturated gases or air to the evaporation chamber toenhance evaporation and latent heat recovery thru percolatingevaporation thus generating a 2-phase flow.
 15. The apparatus of claim14 wherein the fluid flow on the condensation chamber side is always2-phased since it contains both the air/vapor and the condensate. 16.The apparatus of claim 1 further comprising an electrostaticprecipitator operatively connected to the evaporation chamber to purifythe saturated gases provided by the evaporation chamber.
 17. Anapparatus for generating purified liquid from an input liquid,comprising, a condensation chamber comprising an array of panels,wherein each of the panels has multiple channels aligned in a row alonga respective panel, and wherein the multiple channels of the panel arraycomprise a first group of channels and a second group of channels,wherein the second group of channels are perforated to allow the inputliquid to flood the second group of channels, wherein the channels ofthe first group and the second group of channels are interlaced suchthat each one of the channels of the first group is surrounded by theinput liquid, and the purified liquid is outputted at a second end ofthe first group of the channels; a compressor having an inlet and anoutlet, wherein the compressor is operatively connected to theevaporation chamber to receive saturated gases from the evaporationchamber, wherein the compressor is operatively connected to the firstgroup of channels of the condensation chamber, wherein the compressoroutputs supersaturated gases from a pressurization of the saturatedgases to the first group of channels of the condensation chamber via afirst end of the first group of the channels of the condensationchamber, wherein the saturated gases are generated from the inputliquid, wherein the compressor pressurizes the saturated gases togenerate supersaturated gases, wherein the supersaturated gases areexpelled to a first end of the channels via the outlet, wherein thepurified liquid is outputted at a second end of the first group of thechannels, wherein a plurality of walls of the channels are heat exchangewalls, and wherein latent heat is transferred between the input liquidand the channels via the walls of the channels; an evaporation chamberflooded with the input liquid and wherein the evaporation chambergenerates saturated gases and comprises a shared wall with thecondensation chamber and wherein the evaporation chamber is configuredto generate evaporation cavities and condensation cavities on respectivesides of the shared wall for a 2-phase counter flow of a liquid phasecomponent and a gaseous phase component in composite flows for a 2-phaseto 2-phase direct latent heat exchange; a micro bubble generatorconfigured to recirculate a portion of the liquid and gases of thecondensation chamber and the evaporation chamber, wherein the bubblegenerator is configured to permeate the input liquid with percolatinggas bubbles which are adapted to form hanging bubbles beading rightbelow a heat exchange surface of the evaporator chamber; and a P-trapchannel comprising a first end operatively connected the condensationchamber and a second end operatively connected to the bubble generatordisposed in the evaporation chamber, wherein the P-trap channel and thebubble generator are configured to recirculate a portion of thesaturated gasses from the condensation chamber to the evaporationchamber.
 18. The apparatus of claim 17 further comprising, a sedimentchamber operatively connected to the evaporation chamber; and anelectrostatic precipitator to purify the saturated gases operativelyconnected to the evaporation chamber, wherein ends of the second groupof the channels are sealed to prevent the input liquid from flooding thethe first group of the channels, wherein the channels are substantiallyaligned in a horizontal direction, wherein the P-trap channel connectsthe evaporation chamber to the condensation chamber, wherein thepressure in the condensation chamber exceeds the pressure in theevaporation chamber, wherein the sediment chamber is connected to theevaporation chamber for allowing heavier particles in the liquid tosettle in the sediment chamber, wherein the sediment chamber has adigitally controlled pump for pumping the particles from the sedimentchamber, and wherein the sediment chamber has various interconnectedlevels to allow for different particle concentrations at each of theinterconnected levels.
 19. An apparatus for generating purified liquidfrom an input liquid, comprising, a condensation chamber comprisingmultiple channels, wherein the channels are tubes, wherein the multiplechannels comprise a first group of channels and a second group ofchannels, wherein the second group of channels are perforated to allowthe input liquid to flood the second group of channels, wherein thechannels of the first group and the second group of channels areinterlaced such that each one of the channels of the first group issurrounded by the input liquid, and the purified liquid is outputted ata second end of the first group of the channels; an evaporation chamberflooded with the input liquid and wherein the evaporation chambergenerates saturated gases and comprises a shared wall with thecondensation chamber and wherein the evaporation chamber is configuredto generate evaporation cavities and condensation cavities on respectivesides of the shared wall for a 2-phase counter flow of a liquid phasecomponent and a gaseous phase component in composite flows for a 2-phaseto 2-phase direct latent heat exchange; a compressor having an inlet andan outlet, wherein the compressor is operatively connected to theevaporation chamber to receive saturated gases from the evaporationchamber, wherein the compressor is operatively connected to a firstgroup of channels of the condensation chamber, wherein the compressoroutputs supersaturated gases to the first group of channels of thecondensation chamber via a first end of the first group of the channelsof the condensation chamber, wherein the channels are submerged in theinput liquid, wherein the saturated gases are generated from the inputliquid, wherein the compressor receives the saturated gases via theinlet, wherein the compressor pressurizes the saturated gases togenerate supersaturated gasses, wherein the supersaturated gases areexpelled to a first end of the first group of the channels via theoutlet, wherein the purified liquid is outputted at a second end of thechannels, wherein a plurality of the walls of the first group ofchannels are heat exchange walls, wherein latent heat is transferredbetween the input liquid and the channels via the walls of the channels,wherein the tubes each have spacers, wherein the tubes are groupedtogether, and wherein the input liquid flows in between the tubes; and amicro bubble generator configured to recirculate a portion of the liquidand gases of the condensation chamber and the evaporation chamber,wherein the bubble generator is configured to permeate the input liquidwith percolating gas bubbles which are adapted to form hanging bubblesbeading right below a heat exchange surface of the evaporator chamber;and a P-trap channel comprising a first end operatively connected thecondensation chamber and a second end operatively connected to thebubble generator disposed in the evaporation chamber, wherein the P-trapchannel and the bubble generator are configured to recirculate a portionof the saturated gasses from the condensation chamber to the evaporationchamber.
 20. The apparatus of claim 19 further comprising, a P-trapchannel operatively connected to the evaporation chamber and thecondensation chamber for recirculating the portion of the saturatedgases; a sediment chamber operatively connected to the evaporationchamber; and an electrostatic precipitator operatively connected to theevaporation chamber to purify the saturated gases provided by theevaporation chamber, wherein a radial center of each of the tubes areequidistant to the radial center of adjacent tubes, wherein the channelsare substantially aligned in a horizontal direction, wherein a portionof the saturated gases in the condensation chamber are recirculated viaa bubble generation mechanism to the evaporation chamber, wherein theP-trap channel connects the evaporation chamber to the condensationchamber, wherein the pressure in the condensation chamber exceeds thepressure in the evaporation chamber, wherein the sediment chamber isconnected to the evaporation chamber for allowing heavier particles inthe liquid to settle in the sediment chamber, wherein the sedimentchamber having a digitally controlled pump for pumping the particlesfrom the sediment chamber, and wherein the sediment chamber has variousinterconnected levels to allow for different particle concentrations ateach of the interconnected levels.